bug11-class-dummy-extension-len.f90 emits:
STOP 3,
while bug21-assumed-dummy-corrupts-inherited-param.f90 fails with:
14 | real(k) :: e(n + m)
| 1
Error: Parameter ‘k’ at (1) has not been declared or is a variable,
which does not reduce to a constant expression
and
19 | esize = size (a%e)
| 1
Error: ‘e’ at (1) is not a member of the ‘PDTbase_4’ structure
The fix provided by the patch is well described by the ChangeLog and
the comment. The single chunk in trans-array.cc fixes both testcases.
Passes regtesting on FC44/x86_64. OK for mainline.
Cheers
Paul
From 650af45a0430ec0e295b83234c9231c023d585df Mon Sep 17 00:00:00 2001
From: Paul Thomas <[email protected]>
Date: Wed, 7 Oct 2026 10:10:39 +0100
Subject: [PATCH] Fortran: [meta-bug] [PDT] Parameterized derived type errors
[PR82173]
2026-10-07 Paul Thomas <[email protected]>
gcc/fortran
PR fortran/82173
* trans-array.cc (structure_alloc_comps): While recursing into
PDT components, it has to be checked that all the components of
the param_list are explicit before allocating the paramterized
components. If this not the case, use the components own param_
list to replace the assumed expressions.
gcc/testsuite/
PR fortran/82173
* gfortran.dg/pdt_bug11.f90: New test.
* gfortran.dg/pdt_bug21.f90: New test.
---
gcc/fortran/trans-array.cc | 28 +++++++++++++++----
gcc/testsuite/gfortran.dg/pdt_bug11.f90 | 37 +++++++++++++++++++++++++
gcc/testsuite/gfortran.dg/pdt_bug21.f90 | 33 ++++++++++++++++++++++
3 files changed, 93 insertions(+), 5 deletions(-)
create mode 100644 gcc/testsuite/gfortran.dg/pdt_bug11.f90
create mode 100644 gcc/testsuite/gfortran.dg/pdt_bug21.f90
diff --git a/gcc/fortran/trans-array.cc b/gcc/fortran/trans-array.cc
index 80411f9df1a..ab1aa6d457d 100644
--- a/gcc/fortran/trans-array.cc
+++ b/gcc/fortran/trans-array.cc
@@ -11274,17 +11274,35 @@ structure_alloc_comps (gfc_symbol * der_type, tree decl, tree dest,
/* Recurse in to PDT components. */
if ((IS_PDT (c) || IS_CLASS_PDT (c))
- && !(c->attr.pointer || c->attr.allocatable))
+ && !(c->attr.pointer || c->attr.allocatable))
{
- gfc_actual_arglist *tail = c->param_list;
+ gfc_actual_arglist *tail = c->param_list, *parms;
+ bool ext;
+
+ ext = gfc_get_derived_super_type (der_type) == c->ts.u.derived;
for (; tail; tail = tail->next)
- if (tail->expr)
- gfc_insert_parameter_exprs (tail->expr, pdt_param_list);
+ if (tail->spec_type != SPEC_EXPLICIT && tail->expr)
+ break;
+
+ if (tail && ext)
+ /* 'der_type' extends the type of this component but has no
+ type parameters of its own and so some of the components
+ might be assumed. The pdt_param_list will have what is
+ needed. */
+ parms = pdt_param_list;
+ else
+ /* Otherwise, use the component's type parameters. */
+ {
+ tail = parms = c->param_list;
+ for (; tail; tail = tail->next)
+ if (tail->expr)
+ gfc_insert_parameter_exprs (tail->expr, pdt_param_list);
+ }
tmp = gfc_allocate_pdt_comp (c->ts.u.derived, comp,
c->as ? c->as->rank : 0,
- c->param_list);
+ parms);
gfc_add_expr_to_block (&fnblock, tmp);
}
diff --git a/gcc/testsuite/gfortran.dg/pdt_bug11.f90 b/gcc/testsuite/gfortran.dg/pdt_bug11.f90
new file mode 100644
index 00000000000..7e3acdadff9
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pdt_bug11.f90
@@ -0,0 +1,37 @@
+! { dg-do run }
+! See attachment to PR82173 comment 10 - reproducers/bug11-class-dummy-extension-len.f90
+module m4
+ type :: base(k, n)
+ integer, kind :: k = 4
+ integer, len :: n = 1
+ real(k) :: v(n)
+ end type
+ type, extends(base) :: child
+ integer :: extra = 5
+ end type
+contains
+ subroutine show (c)
+ class(base(4, *)), intent(in) :: c
+ select type (c)
+ type is (base(4, *))
+ if (c%n /= 3) stop 1
+ if (size (c%v) /= 3) stop 2
+ type is (child(4, *))
+ if (c%n /= 5) stop 3
+ if (size (c%v) /= 5) stop 4
+ if (c%extra /= 42) stop 5
+ class default
+ stop 6
+ end select
+ end subroutine
+end module
+program i4
+ use m4
+ type(base(4, 3)) :: b
+ type(child(4, 5)) :: c
+ b%v = 0.0
+ c%v = 0.0
+ c%extra = 42
+ call show (b)
+ call show (c)
+end program
diff --git a/gcc/testsuite/gfortran.dg/pdt_bug21.f90 b/gcc/testsuite/gfortran.dg/pdt_bug21.f90
new file mode 100644
index 00000000000..2881bd2b903
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pdt_bug21.f90
@@ -0,0 +1,33 @@
+! { dg-do run }
+! See attachment to PR82173 comment 10 - reproducers/bug21-assumed-dummy-corrupts-inherited-param.f90
+module base4_m
+ type :: base(k, n)
+ integer, kind :: k = 4
+ integer, len :: n = 1
+ real(k) :: b(n)
+ end type
+end module
+module ext4_m
+ use base4_m
+ type, extends(base) :: ext(m)
+ integer, len :: m = 1
+ real(k) :: e(n + m)
+ end type
+contains
+ integer function esize (a)
+ type(ext(4, *, *)), intent(in) :: a
+ esize = size (a%e)
+ end function
+end module
+program u4
+ use ext4_m
+ type(ext(4, 2, 3)) :: x
+ x%b = 1.0
+ x%e = 2.0
+ if (x%k /= 4) stop 1
+ if (x%n /= 2) stop 2
+ if (x%m /= 3) stop 3
+ if (esize (x) /= 5) stop 4
+ if (int (sum (x%b)) /= x%n) stop 5
+ if (int (sum (x%e)) /= 2 * (x%n + x%m)) stop 6
+end program
--
2.55.0
